fizzics » Standard Grade

booklets for all standard grade physics units

mrmackenzie — Tue, 24 Apr 2012 19:00:58 +0000

I’ve been asked to post a link to all of the booklets so that people have access to something like the energy booklet as they revise using electricity and electronics. I’ve added these to the standard grade page now. Look for a link called whole unit notes in each section.

For those of you who have yet to download a copy of the SQA Physics booklet, get yours here.

robot radiotherapy

mrmackenzie — Mon, 16 Apr 2012 09:23:45 +0000

Last week, the BBC broadcast a Horizon programme about new cancer treatments being trialled at the Royal Marsden Hospital in London. The documentary followed three different types of treatment; robotic surgery, a genetically targeted drug and a radiotherapy robot.

As we’ve discovered, standard radiotherapy treatment involves splitting the required dose into 3 beams, so only cells inside the tumour receive the full dose. The radiotherapy robot, CyberKnife, allows high energy x-rays to enter the patient’s body from many different angles. The advantage of this robot is that it minimises the risk to healthy tissue while ensuring a fatal dose of energy is delivered to the cancer cells.

I have put together a series of clips from the programme to follow patient Ray’s treatment. The clip from the planning meeting shows just many individual beams the robot will use during the treatment.

To find out more about how x-rays affect living cells, watch this clip from Bang Goes the Theory.

The Royal Marsden Hospital has a video that provides a quick guide to radiotherapy.

Use the download link below if you would like to save a copy of the CyberKnife video.

how satellites rule our world

mrmackenzie — Mon, 26 Mar 2012 19:02:28 +0000

BBC2 showed a really good programme about satellites last night. This screenshot showing a satellite passing over the Highlands is taken from about 17 minutes into the show. Click on the picture to visit the BBC’s own page about the documentary.

It was quite eye-opening to see just how much modern society relies on satellite technology.

You can download the entire programme using the link below.

S3 credit electricity revision

mrmackenzie — Tue, 20 Mar 2012 19:41:47 +0000

If you found the general test tricky, here is something to help you prepare for the credit test on Thursday morning. Click on the download link to get your own copy of a full set of notes on the Using Electricity unit.

Thanks to Mr Cunningham for sharing these notes.

ray diagram revision

mrmackenzie — Tue, 20 Mar 2012 14:59:12 +0000

We’ve reached the Space unit and are almost at the end of the course. I showed you how to draw ray diagrams when we looked at lenses during the Health Physics unit. Some people have asked me to repost these video clips as they were not sure how to draw ray diagrams for our telescope this morning.

Watch these clips and make sure you know the six terms we use to describe the image formed by a lens. You should be able to select three words to describe the image in your ray diagram.

how to draw a ray diagram from mr mackenzie on Vimeo.

The second video looks at a ray diagram when the object is less than one focal length away from the lens.

ray diagram for objects closer than 1f from mr mackenzie on Vimeo.

Once the ray diagram is complete, we need to describe the image that has been formed. The description must tell us about the size, orientation and type of image that is formed.

Size
If the image is larger then the original object, we say the image is magnified
If the image is smaller than the original object, we say the image is diminished.

Orientation
If the image is the same way up as the object, we describe it is upright.
If the image is upside down compared to the object, we describe it as inverted.

Type
If the object and image are on opposite sides of the lens, it is a real image.
If the object and image are on the same side of the lens, it is a virtual image.

S3 electricity revision

mrmackenzie — Sun, 18 Mar 2012 17:20:43 +0000

Here’s some mains electricity revision for the cat lovers in S3. Remember that your tests are on Tuesday and Thursday. Ignore the 5A fuse stuff in the link, you should always select a 3A or 13A fuse.

electric motors

mrmackenzie — Tue, 13 Mar 2012 19:36:52 +0000

 
 image by explainthatstuff

We’re finishing off the electricity unit by looking at electric motors. The page I used in class to help explain how a simple electric motor works is available here.

Here is another nice animation that shows the key parts of an electric motor. It will stop after a few rotations but just reload the page to see it again.

Real electric motors have a few modifications;

they use field coils instead of a bar magnet – the field coils form a strong electromagnet when current passes through them. The field coils do not rotate.
the single rotating coil is replaced by several rotating coils
there are more contacts on the commutator – each pair connects to a different rotating coil
the brushes are often made from carbon instead of metal – the carbon conducts electricity and can withstand high temperatures. Carbon also moulds to the shape of the commutator to give a good electrical contact

image by marrrci

S3 the kilowatt-hour

mrmackenzie — Mon, 05 Mar 2012 19:10:24 +0000

Recently we looked at the way power companies calculate how much electrical energy we use in our homes. The Joule is too small a unit to measure household energy consumption, so suppliers work out our bills using a must larger unit called the kilowatt-hour (kWh).

I found this page on BBC Bitesize that has some information and a quiz to test your kWh knowledge. There is also a section on the kilowatt-hour at gcse.com.

dropping a slinky

mrmackenzie — Fri, 02 Mar 2012 16:41:28 +0000

Ria asked if a slinky really stops in mid air when it is released. Eoin helped us to find out the answer.

It’s easier to see what happens if you watch a slow motion version.

Or even slower motion.

Why does that happen?

high frequency sound on a tv advert

mrmackenzie — Sat, 18 Feb 2012 17:19:40 +0000

A dog food company has launched the first TV advert aimed directly at dogs themselves. The advert’s soundtrack includes sounds with frequencies in the range 18 000 to 20 000 Hz (18-20 kHz). Dogs can hear sound with frequencies greater than 20 kHz, we call this ultrasound.

I found a copy of the advert on Youtube. The upper limit of human hearing is 20 kHz, so some young people should be able to hear the sounds for themselves even though adults can’t. Can you?

http://www.youtube.com/watch?v=7SwW1dkselY

Now let’s see what happened when the BBC Newsround team filmed some dogs while the advert played in the same room.

http://www.youtube.com/watch?v=lxwDu7Q8oOQ

You might have used a signal generator in class to discover your personal upper frequency limit. The video below has a soundtrack that starts at 1 Hz and sweeps up to 20 000 Hz, before sweeping back down to 1 Hz again. For how long can you hear the sounds?

http://www.youtube.com/watch?v=VX47rAxzhKA